1. Field of the Invention
The present invention relates generally to a head core slider for a rigid magnetic disk drive (RDD) and a method of fabricating the same, and more particularly to a technique for reducing or avoiding a noise in the form of abnormal pulses, which may occur during reproduction or reading of recorded signals, particularly in a magnetic recording head for RDD using a ferrite core slider.
2. Discussion of the Prior Art
As one type of head core slider for a rigid magnetic disk drive (RDD), which includes a slider body having air bearings and a head core having a closed magnetic circuit (path) with a magnetic gap, there is known a ferrite core slider for RDD, in which at least a head core portion constituting the closed magentic circuit is formed of a ferrite material.
Various types of ferrite head core sliders have been proposed for use in a magentic head, for improvements in the output, recording density and other characteristics of the magnetic head. For instance, there are proposed a so-called monolithic type core slider, a so-called composite type core slider and a core slider having a MIG (Metal In Gap) structure. In the monolithic type core slider, the whole body of the core slider is formed of ferrite, and a part of the slider body functions to partially define the closed magnetic circuit. In the composite type core slider, the slider body and the head core are prepared independently of each other, and only the head core portion constituting the closed magnetic circuit is formed of a ferrite.
In operation of the RDD magnetic head having the ferrite core slider of any known type, reproduction outputs may include noise in the form of abnormal pulses (which may be called "Wiggle"), upon reproduction of signals recorded on a magnetic disk. Formerly, this abnormal-pulse type noise did not cause any major problem since the noise has a relatively low output level. Up to the present, therefore, the cause for the occurrence of this type of noise has not been made clear nor discovered, let alone a solution to the problem.
In recent years, however, the RDD magnetic head may suffer from increases in the output level and frequency of occurrence of the abnormal-pulse type noise, due to an increased coercivity of a magnetic disk to meet a need for high-density recording, an increased residual magnetic flux density, and a comparatively narrow spacing between the magnetic head and magnetic disk.